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I have 2002 ls430 Lexus cannot get 5 volts from ecm to knock

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I have 2002 ls430 Lexus...
I have 2002 ls430 Lexus cannot get 5 volts from ecm to knock sensors
Submitted: 1 year ago.Category: Lexus
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Answered in 1 minute by:
10/31/2016
Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago
David Craig
David Craig, Auto Mechanic
Category: Lexus
Satisfied Customers: 4,472
Experience: Owner/Mechanic at 3D Automotive
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Hi Im David, thanks for visiting the site, allow me a moment to look up some information for you. thank you.

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Customer reply replied 1 year ago

hello what do you need to know

Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

i dont need to know anything. im going to let you know what i thinks going on with your vehicle. thanks.

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Customer reply replied 1 year ago

according to Aldata there is suppose to be 5 volts from ECM to sensors which comes from plug e6 pin 1&2 which ohm out and that is the wires but no volts

Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

please give me a moment

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Customer reply replied 1 year ago

no problem going to eat supper check you in a few

Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

the knock sensor wires are located at D1 & D2 of that connector. you need to also check the shield ground for the sensor wiring to A15

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Customer reply replied 1 year ago

where and how to check shield wiring and why am I not getting 5 volts from ECM pins 1 and 2 on plug e6 Also on the knock sensor print out I have it says that if you use flat type sensor the ECM supplies 5 volts. Dose anyone know how to repair this car .

Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

shielded wires are part of the insulation that surrounds the conductor insulation. its usually braided. you would check it by probing the outer insulation jacket of the sensors connector with one lead and doing a continuity check of it to A15

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Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

if the ecm isnt supplying the volts then i suggest you check the grounds around the ecm mounting area and related ecm fuses

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Customer reply replied 1 year ago

Is the braided wire around the wire that runs to the sensors and is a15 in which terminal my diagram has them # e2 thru e6

Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

Using an ohmmeter, check that there is no continuity between the terminal and body of the sensors
If there is continuity, replace the sensor. is that what you did before you replace them?

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Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

there are so many fuses on this vehicle that control some output of the engine control. fuses that even labeled you would have no idea they had anything to do with the engine control

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Customer reply replied 1 year ago

I was an idiot I took for granted that the codes were right and I pulled intake and bought two sensors from Lexus and replaced them and then found out that is not the problem. The last set of images you sent is what they show from Aldata for this car . I don't see any signs of braided wire even though the image shows some type o shielded wire. I did run continuity test on sensors and wiring the second time I took off intake before I bought new ECM . Now I have intake off for the third time and would like to repair it customer I s getting angry and I am tired

Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

pick it back up tomorrow?

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Customer reply replied 1 year ago

I have checked and ohm every fuse I could find still not getting 5 volts coming out of ECM

Customer reply replied 1 year ago

are you there on yet

Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

im here

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Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

the only thing it can be is the ecm. replace it.

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Customer reply replied 1 year ago

I did same results

Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

replace it with a new one. and have it programmed to your vehicle... it cant be anything else if youve checked the wires from the ecm to the injectors. either that or you are missing a ground at the ecm

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Customer reply replied 1 year ago

first of did you mean knock sensors I am not concerned with injectors and also were are the grounds for ECM located

Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

sorry, yes the knock sensors

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Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

access the ecm and follow the harness you will find the grounds. should be in the immediate area

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Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

any update?

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Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

hello??

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Customer reply replied 1 year ago

still not working going to try something else today will let you know

Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

theres nothing left to try except some ecm related fuse.., if the wiring ohms out good to 15A, D1 and D2, and D1 and D2 arent reading to ground, theres nothing else.

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Customer reply replied 1 year ago

can you send me a diagram of were 15A is in the ECM plugs and which plug you are using to make sure I am checking the correct wires

Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

give me a while to dig that info up. thanks

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Customer reply replied 1 year ago

ok

Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

any update?

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Customer reply replied 1 year ago

starting back to work on it this morning

Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

ok. keep me updated and ill keep digging

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Customer reply replied 1 year ago

you are saying to use pi 32 and pin 35 for the knock sensors my aldata my diagram shows e1 and e2 in pin plug e6

Customer reply replied 1 year ago

from your diagram I can see we are in the same pin plug you got make sure that pin numbers are correct because the wires that I ohm out are 1 white and 2 black and they ohm all the way back to knock sensor plug

Customer reply replied 1 year ago

in your early response you 15a d1 and d2 is 15a pin plug e6 that is middle plug of 3 plug combanation if so I have the right wires because 32 is brown and 35 is black if that is the case I am in the wrong the wires going to or coming from ECM have to be black and white according to wiring diagram

Lexus Mechanic: David Craig, Auto Mechanic replied 1 year ago

ok, let me get home and i will look in to this thoroughly

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